This invention relates to postage metering systems and postage meters and in particular to such systems and meters in which use of the machine is restricted to authorised users.
Postage meters are utilised to print franking impressions on mail items to indicate that the postage charges for those items have been accounted for. If the postage meter is operated in pre-payment mode, a value of credit is stored in the meter and is decremented by an amount equal to the postage charge as each mail item is franked. If the postage meter is operated in post payment mode payment is made to the postal authority periodically in respect of an accumulated value of franking transactions recorded by the meter. Such postage meters are well known.
It will be appreciated that a postage meter located in premises of a user may be operated without permission of the user for mail other than that being mailed by the user of the postage meter. As a result persons other than the user may frank mail items without cost to themselves and the cost of postage charges for those items will be borne by the user. Previously, use of postage meters has been restricted to authorised personnel by providing the meter with a key operated switch and issuing the corresponding key only to a person authorised to use the postage meter. However the need to use a key is inconvenient and a key operated switch is not satisfactory in preventing unauthorised use of the postage meter if a person authorised to use the postage meter neglects to remove the key from the postage meter after use of the meter thereby enabling anyone to use the meter. It has also been proposed to require a user to key in, on a keyboard of the meter, a personal identification number (PIN) and, if the PIN is recognised by the meter as an authorised PIN, the postage meter then becomes operative to permit use of the postage meter for carrying out franking operations in respect of mail items. Although the use of a PIN to enable the postage meter does not have all of the disadvantages associated with use of key operated switch, knowledge of the PIN may become known to persons other than the authorised person and those other persons are then able to use the postage meter.